Proteins have been widely used as ingredients in personal care products to perform a variety of functions and to impart desired characteristics to product formulations. For example, proteins have been used to impart manageability and strength to hair, to moisturize skin and hair, and to provide film formation to improve the appearance of skin and hair. Proteins have also been used to provide durability properties to many personal care products.
However, such proteins may not exhibit all desired characteristics when used in personal care products. For example, natural silk proteins may impart durability but may also form tight, hard fibers that are not suitable for film formation. Also, many natural proteins have a low isoelectric point, which reduces the affinity of the protein for the negatively charged skin and hair. Additionally, when more than one protein is needed to impart all desired characteristics to a given formulation, the necessity of using more than one protein may increase the cost and production time for a given personal care product.
Furthermore, proteins generally have poor solubility due to high molecular weight and hydrophobicity. Commercially available proteins, including structural proteins such as silk and collagen, are typically chemically degraded giving a diverse mixture of molecular weight fragments with variable properties. As such, these proteins are often modified chemically to enhance solubility for inclusion in personal care products. However, even chemically modified proteins may not have all desired characteristics.
Thus, there remains a need in the art for personal care compositions that have desired characteristics without chemical modification of the proteins. There also remains a need in the art for a method of delivering a protein into a personal care composition so as to effectively deliver the protein in a useable form.